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4 years ago

Solve using any method.

Mathematics

2 answers:

Klio2033 [76]4 years ago

7 0

The answer should be 4. (2, 1)

GaryK [48]4 years ago

3 0

The fourth one since -2(2) would be -4 then the y is 1 which would make it into -4+1=-3 and it’s the same as the fourth one

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154 and 145 to the nearest hundred

Yuki888 [10]

Answer: 154: 200 145: 100

Step-by-step explanation:

If the number next to the place value is 5 or more you round it up. Like I did 154. But if the number is less that 5 you put everything to zero EXCEPT for the place value you are rounding. Good Luck

5 0

3 years ago

Read 2 more answers

if the cost of 3 chocolates and 2 cookies is $22 and that of 2 chocolates and 3 cookies is $18, what is the cost of cookies.

Vanyuwa [196]

Answer:$2

Step-by-step explanation:Express as two equations . Lex x Be chocolate and y be cookies.

3x+2y=22

2x+3y= 18

Common factor of 6 so times first ran by 2, second ran by 3 . Eliminate.

4 0

3 years ago

Read 2 more answers

Calculate s f(x, y, z) ds for the given surface and function. g(r, θ) = (r cos θ, r sin θ, θ), 0 ≤ r ≤ 4, 0 ≤ θ ≤ 2π; f(x, y, z)

Triss [41]

$g(r,\theta)=(r\cos\theta,r\sin\theta,\theta)\implies\begin{cases}g_r=(\cos\theta,\sin\theta,0)\\g_\theta=(-r\sin\theta,r\cos\theta,1)\end{cases}$

The surface element is

$\mathrm dS=\|g_r\times g_\theta\|\,\mathrm dr\,\mathrm d\theta=\sqrt{1+r^2}\,\mathrm dr\,\mathrm d\theta$

and the integral is

$\displaystyle\iint_Sx^2+y^2\,\mathrm dS=\int_0^{2\pi}\int_0^4((r\cos\theta)^2+(r\sin\theta)^2)\sqrt{1+r^2}\,\mathrm dr\,\mathrm d\theta$

$=\displaystyle2\pi\int_0^4r^2\sqrt{1+r^2}\,\mathrm dr=\frac\pi4(132\sqrt{17}-\sinh^{-1}4)$

###

To compute the last integral, you can integrate by parts:

$u=r\implies\mathrm du=\mathrm dr$

$\mathrm dv=r\sqrt{1+r^2}\,\mathrm dr\implies v=\dfrac13(1+r^2)^{3/2}$

$\displaystyle\int_0^4r^2\sqrt{1+r^2}\,\mathrm dr=\frac r3(1+r^2)^{3/2}\bigg|_0^4-\frac13\int_0^4(1+r^2)^{3/2}\,\mathrm dr$

For this integral, consider a substitution of

$r=\sinh s\implies\mathrm dr=\cosh s\,\mathrm ds$

$\displaystyle\int_0^4(1+r^2)^{3/2}\,\mathrm dr=\int_0^{\sinh^{-1}4}(1+\sinh^2s)^{3/2}\cosh s\,\mathrm ds$

$\displaystyle=\int_0^{\sinh^{-1}4}\cosh^4s\,\mathrm ds$

$=\displaystyle\frac18\int_0^{\sinh^{-1}4}(3+4\cosh2s+\cosh4s)\,\mathrm ds$

and the result above follows.

4 0

4 years ago

Solve for the following equation x^2+9x+14=0

sergejj [24]

Answer:

<em>R</em><em>=</em> {-7,-2}

Step-by-step explanation:

divide 14 into 2 and 7 because 2x7=14
write the equation as a multiplication of (x+7) and(x+2) =0
for the result to equal zero. at least one of the factors must equal zero, therefore we get two solutions

5 0

3 years ago

PLEASE HELP ME FIND X

wel

x = 19

...........

7 0

3 years ago